The goal of our research protocols is to determine how the regulation of cytokine synthesis differs in allergic and non-allergic individuals. Toward this end, our objectives are to determine the cellular and molecular mechanisms that control IL-4 expression in CD4+ T cells. In some of these studies, we are focused on determining the role of antigen presenting cells and the role of genetic predisposition on cytokine synthesis in CD4+ T cells. The studies performed in the GCRC involve examination of alveolar macrophages from the lungs of allergic and non-allergic individuals, and determining how such antigen presenting cells influence cytokine production and how they induce tolerance in T cells. These studies of cytokine regulation in CD4+ T cells will lead to a better understanding of the critical immunologic responses that underlie allergy and tolerance induction. Such an understanding will be key in the design of novel immunotherapies for diseases such as allergy and autoimmunity.